Equine anthelmintic resistance: Anthelmintic efficacy in Parascaris spp. (ascarids) populations in foals and youngstock and existing management strategies on UK stud farms.

The increasing prevalence of anthelmintic resistance (AR) in horse endoparasites threatens to significantly compromise health and welfare through a reduced ability to control parasite-related disease. Therefore, there is a critical need for action to protect the future effectiveness of anthelmintics by slowing the development and spread of AR. A new pan-industry equine group (CANTER - Controlling ANTIparasitic Resistance in Equines Responsibly) has been formed to consider and advise on sustainable control of parasites and the VMD has representation on the Core Steering Group. <br/><br/>CANTER’s initial priority is to publish evidence-based best practice guidelines for use of anthelmintics, with the aim to delay further development of resistance. Ongoing research is required to inform these guidelines. <br/>CANTER's website can be found at canterforhorses.org.uk ↗ <br/><br/>Ascarids are one of the most common and clinically important roundworms infecting young horses. Worldwide, there is evidence of resistance in equine ascarid populations to the macrocyclic lactone class of anthelmintics and that resistance to the benzimidazole and tetrahydropyrimidine classes is increasing. However, there is limited UK-specific information on resistance in ascarid populations. Management of this important parasite is likely to become more challenging on UK stud farms, with increasing concerns regarding the development and spread of AR. <br/><br/>The VMD is launching this call for interest to undertake research to address an important gap in current knowledge regarding current efficacy of the different authorised anthelmintic classes in ascarid populations in foals and youngstock in the UK. Promoting responsible use of anthelmintics is essential to protect the future effectiveness of these medicines and the health and welfare of UK horse populations, alongside minimising environmental impacts. <br/><br/>Further understanding ascarid egg shedding patterns as well as management strategies are also required to inform development of new strategies to delay further development of resistance. Such work to investigate efficacy of anthelmintic treatment in ascarid populations should also include exploration of current management strategies employed by a range of UK stud farms and examination of ascarid egg shedding dynamics in foals and youngstock in the UK.<br/><br/>The data collected from this work will: provide useful UK-specific baseline data on anthelmintic efficacy to allow future work to determine further development and spread of AR; identify management factors influencing efficacy of anthelmintic treatment; identify factors contributing to variance in ascarid prevalence and egg shedding dynamics in UK foals and youngstock; provide valuable information on current management strategies and uptake of recommendations considered to be best practice from a range of different equine establishments; and highlight opportunities for practical intervention to increase uptake of best practice principles by stud farms. This research will help to inform the VMD’s anthelmintic resistance policy, alongside improving animal health, welfare and productivity through enhanced anthelmintic stewardship programmes.<br/><br/>Whilst welcoming applications from all interested organisations, it is recognised that the complexity of this project may make it suitable for an early-stage researcher or PhD programme. Additional information: If you would have any questions on this PIN or would like to register interest, please contact Network.Procurement@defra.gov.uk